Telephone-transmitter



2 Sheets-Sheet 1.

W. BURNLEY.

TELEPHONE TRANSMITTER.

(No Model.)

No. 335. 502. Patented Feb. 2 1886.

.1" uveidor. Williamjurwlqy) N. PETERS, wh wumo n m. Wuhinglnm n. c.

(No Model.) 2 SheetsSheet 2. W. BURNLEY.

TELEPHONE TRANSMITTER.

No. 335,502. Patented Feb. 2, 1886.

a I I HIIUIIHMW Inventor,

WiZZiaMMT /Zey uZ-Zi'zn g a" ma UNITE SrArns IVILLIAM BURNLEY, OF NORTH EAST, PENNSYLVANIA, ASSIGNOR OF TWO- THIRDS TO CHARLES A. HITOHCOOK, OF SAME PLACE, AND LEYVIS F. \VATSON, OF \VARREN, PENNSYLVANIA.

TELEPHONE-TRANSMITTER.

SPECIFICATION forming part of Letters Patent No. 335,502, dated February 2, 1886.

Application filed April 11, 1885. Serial No. 161,921. (No model.)

To all whom, it may concern: To these ends the invention consists in the 50 Be it known that I, \VILLIAM BURNLEY, a features more particularly hereinafter decitizen of the United States, residing at North scribed and claimed, reference being had to East, Erie county, Pennsylvania, have inthe drawings, in Which- 5 vented new and useful Improvements in Tele- Figure 1 is aside view of asingle diaphragm phonic Transmitters, of which the following and its electrodes; Figs. 2 and 3, a top and 55 is a specification. end view, respectively, of a detail thereof;

In telephonic transmitters as usually con- Fig. 4, a plan view of the front of the multistructed the diaphragm is combined with two ple transmitter; Fig. 5, a front view of the IO electrodes and proper circuit and line connecmouth-piece thereof; Fig. 6, a side View of tions, so as to control through the medium the multiple transmitter; Fig. 7, a section 60 of the electrodes the current traversing the thereof on line aof Fig. 6. Fig. 8 is a side line. Multiple transmitters have also been View of a dust-protector for the diaphragms constructed in which a series of sets of elecand electrodes. Fig. 9 is a longitudinal sec- I trodes were controlled byasingle diaphragm, tion of an electrode. Fig. 10 is a plan view the several sets of electrodes being insulated of an electrode and the'plate on which it rests. 6 from each other and connected up in inde- Fig. llisa view showingamultiple telephone pendent local circuits, which they controlled, case opened. and which were the primary circuits of induc- The general plan of each diaphragm and its tion-coils, the secondary circuits whereof were controlled set of electrodes is such that an connected to one main line, either in series or electrode formed of a carbon pencil or rod is 7c in multiple arc, the object being to throw a attached by an intermediate rubber block to greater amount of properly varied current the diaphragm, while the other electrode, also upon the line, to the end that the line might a carbon pencil, lies loosely upon an inclined be lengthened and telephonic transmission metallic plate, the normal contact between the effected over an increased distance. The two being due to the gravity of the latter elec- 7 5 weighting down of a single diaphragm, howtrode, the contact being aided by a weight or ever, by a number of electrodes I have found ballast attached to an electrode or lying upon tends to render the diaphragm sluggish, and both. This is shown in Figs. 1, 2, and 3, in

0 to require an increased volume of powerful which the reference-numeral l indicatesa diasound-waves to make it respond quickly and phragm, to which is attached, by means of the 8c perfectly. In addition, the exact adjustment rubber block 2, the pencil or rod electrode 3. of a whole series relatively to one diaphragm 5 is an inclined plate, upon which rests the is a matter of difficulty .and delicacy. pencil or rod electrode 4, contacting with 1 by 3 5 The object of my invention, therefore, is to its gravity. A weight or ballast, 12, preferconstruct a multiple transmitter in which a ably of rubber, lies upon the two electrodes, 85 series of diaphragms, each controlling an inand aids in normally maintaining good condependent set of electrodes, shall be used, and tact between them. This weight or ballast 12 in such manner that all the diaphragms are has a central recess, 14, to pass around the actuated by the same sound-vibrations. Each block 2 without interference therewith, while set of electrodes has its own circuit and baton the other side of the recess its body is 0 tery connections, which may be the primary tapered and bent downward, forming the circuits of independent induction-coils, whose hooked part 13, by which it catches upon the secondary circuits are connected, either in seelectrode 1 and is kept in position.

5 ries or in multiple circuits, to a main line; or The plate 5 may be provided with legs 6,

all the sets of electrodes may control localby which it may be attached to a suitable base 5 circuit connections to a single primary coil of or support, as shown in part of Fig. 7, though an induction-coil whose secondary coil is conthese may be dispensed with, as shown in nected to line. another part of the same figure. Suitable circuit-connections are made to the electrodes by a wire, 21, connected to the plate 5, and a wire, 20, connected to the electrode 1. I propose to use a number of such diaphragms and sets of electrodes in a single transmitter, ar-J ranging them so that all are equally under the influence of the same sound-waves. In the illustrations here given and herein to be de scribed, eight such diaphragms and sets of electrodes are shown; but I am not confined to such number, as any desired number may be used, the number eight being here used arbitrarily for sake of illustration only.

For ease of construction and mounting,each pair or set of diaphragms is mounted in a base consisting of three sections-an outer one, 22, a middle one, 23,, and an outer one, 24. Through 23 are made one or more apertures, 25, slightly smaller than the diaphragms, upon each side of which a diaphragm, 1, is secured. A recess of the same size is sunk to a slight distance in 22 and 24, while an opening is cut entirely through them above the center of the diaphragms, the openings having inwardlyinclined bottoms for supporting the plates 5, as clearly shown in Fig. 7. The result is, that a number of air or wave chambers are formed of the apertures 25, each having a diaphragm on the sides thereof. In Figs. 4 and 7 two such sound-chambers are shown in each half, and if the two halves be united by hinges and secured together by hooks 26, the organization has four sound-chambers and eight independent diaphragms and sets of electrodes. In order to conduct the sound -vibrations equally to all these chambers, air-passages 8 are made therefrom, which are inclined as shown in dotted lines in Fig. 6. A monthpiece, 9, is used, having the orifice 10 for the mouth, from whence lead inclined passages 11, the passages 11 and 8 being so arranged that I when the mouth-piece9 is secured to the front by pins 17 taking into apertures 15, 11 and8 register, and each two form one complete passage from 10 to a chamber, 25. Each set of electrodes has its circuit and battery connections 20 21, which may be the primary circuits of independent, induction -coils, whose secondary circuits are connected, either in series or in multiple circuits, to a main line; or all the sets of electrodes may control local-circuit connections to the single primary coil of an induction-coil whose secondary coil or coils are connected to the line. I prefer, however, to use therewith an induction-coil having a number of independent primary coils, one for each set of electrodes, upon the same core and a single secondary coil connected to the line. This is not shown in this case, however, as it will form the subject'matter of a separate application. Thus all the diaphragms and sets of electrodes are placed equally under the influence of the same sound-vibrations, and a multiple transmitter is formed of great power, readily operated, yet adapted to throw upon a line agreat quantity of largely-varied current, whereby the distance it may be used for transmission is greatly increased. Vhen it is only desired to use two diaphragins and their sets of electrodes, the mouth piece 9, with passages 11, may be dispensed with, and a plain or ordinary mouth-piece opening directly into the chamber 25 be used.

The construction as thus far describedis of the simplest form, and there may arise therein certain dangers which it is best to guard against, as hereinafter noted. As the electrodes are carbon rods or pencils contacting along an axial line upon their circumferences, it is essential that their axes be maintained parallel. Some irregularity or protuberance, scarcely if at all visible to the eye or discoverable, may prevent this parallelism, the cause being in either electrode or in the plate, and being more serious when occurring near the center of gravity of the loose electrode. One method of obviating this is shown in Fig. 9,

wherein the loose electrode 4 is slightly, for

about the space of one-fourth to one-half an inch, hollowed at its center, while upon each end, beyond this hollowed portion, may be placed platinum bands 30. Instead of the electrode being thus hollowed, a slot may be cut in the plate 5, leaving it a frame upon which the electrode 4 rests at or near its ends. Another plan is shown in Fig. 10, wherein the plate 5 is provided with slightly-raised tracks or ways 32, preferably of a platinum strip or wire soldered to the plate, while the electrode 4 has grooves 31 cut around it,wh-ich take upon 32. This slightly raises4 from 5, and prevents also any endwise motion of 4 upon 5, the electrical connection between the two being preserved by the platinum.

It is a fact that the dust which is constantly floating in the air will, if permitted access to and deposition upon the electrodes, soon lessen and ultimately destroy their usefulness for controlling and varying the circuit. In order then to protect the electrodes when they otherwise would be exposed to this danger, a device like that shown in Fig. 8 is used. 27 is a screw-threaded base, which is secured to the side or base supporting the electrodes by being glued or fastened thereto, or by taking into a recess cut therein for its reception, as shown upon the right-hand side of Fig. 7. Upon this screws the cap 28, the whole for1ning a dust-proof cap or protector for the electrode where applied. In order to more thoroughly guard the interior of the case against access of dust, a packing strip of felt, rubber, or cloth, 33, may be applied to one of the sections, as section 35 in Fig. 11. When the two sections are closed together, as in Fig. 4, the compression of this packing between the sections serves to make a dustproof joint and effectually protect the interior of the case.

Having thus described my invention, what I claim is- 1. In a telephonic transmitter, the combination of a diaphragm, a carbon rod secured thereto by a rubber block, an inclined metal-.

lic plate, a loose carbon rod lying thereon and normally contacting with the first-mentioned rod, a weight or ballast of rubber for lying upon these rod-electrodes, and formed with a hook, whereby it is attached to one of the electrodes, substantially as described.

2. In a telephonic transmitter, the combination of the section 23, having the soundchamber 25 formed therein, the sections 22 and 24, carrying the plates 5, supporting the electrodes 4, two diaphragms secured upon opposite sides of the chamber,and circuit-connections, substantially as described.

3. In a telephonic transmitter, the combination of a diaphragm, a carbon-rod electrode secured thereto, a plate, 5, having lugs or 

